The best note: Parallel Twin with Dunstall reverse cone "Decibel" Slip-Ons.
The worst note: Harleys, they sound too much like a Yamaha Road Star. They even sound slow.
(I'm serious, by the way - I just don't like the HD sound)
A well tuned Triumph twin with Dunstall pipes is the sweetest note out there. Extremely deep tone and not loud at all - until you burn the glass out of the muffler. You can even hear a little puff of air with each pulse.
Here's a link. She's got her baffles in, but no fiberglas:
Dunstall Pipes On A NewBonneville
